Need some help
I really depends on what you want to plot. You can plot the cumulative count of the sign changes with: x <- sample(c(0,1), 1000, TRUE) plot(cumsum(x), type='l') There are other things you can do. You can get a rough histogram of the length of the run by:
stem(rle(x)$length)
The decimal point is at the | 1 | 00000000000000000000000000000000000000000000000000000000000000000000+201 1 | 2 | 00000000000000000000000000000000000000000000000000000000000000000000+60 2 | 3 | 00000000000000000000000000000000000000000000000000000 3 | 4 | 00000000000000000000000000000000000000 4 | 5 | 000000000 5 | 6 | 00000000 6 | 7 | 00000 With R, almost anything is possible.
On 10/15/07, azzza <azza.khogaliali at utoronto.ca> wrote:
Umm, yes, what you had makes a lot of sense. How would I represent that in a plot of the number of sign changes in the to Y axis, and the toss number (from 0 to 1000) in the x-axis? jholtman wrote:
You might want to check out 'rle'. This will give you the 'lengths' of runs of the same value and therefore when the value changes (sign change?) you can see how often:
x <- sample(c(-1,1), 1000, TRUE) rle(x)
Run Length Encoding lengths: int [1:483] 2 2 1 4 3 1 1 1 1 2 ... values : num [1:483] -1 1 -1 1 -1 1 -1 1 -1 1 ... Here was a sample of 1000, and there were 483 changes between the samples. Is this what you are looking for? On 10/15/07, azzza <azza.khogaliali at utoronto.ca> wrote:
Quite helpful indeed. Greatly appreciated. Another problem I had was trying to simulate an example from my book. Simulating 1000 coin tosses, and finding the frequency of sign changes. So how will we plot this using R? (frequency of sign changes in Y axis) Daniel Nordlund wrote:
-----Original Message----- From: r-help-bounces at r-project.org
[mailto:r-help-bounces at r-project.org]
On Behalf Of azzza Sent: Sunday, October 14, 2007 10:21 PM To: r-help at r-project.org Subject: [R] Need some help Hi! I'm taking a course that requires some programming background, but I'm
a
complete novice in the field. when asked to generate a list of 20 uniform random numbers, is it
alright
if I put in >randu, and just copy-paste the first 20 numbers?? Or is
there,
as I suspect, a better way of calling out exactly 20 uniform random numbers??
See ?runif rand_nums <- runif(20)
I'm also unable to solve the following problem: We know that on average 30% of the customers who enter a store make a purchase. Suppose 200 people enter the store today. Run a simulation to see how many
purchases
we will have today.
see ?sample
number_of_purchases <- sum(sample(c(0,1), 200, prob=c(.70, .30), replace=TRUE))
Hope this is helpful, Dan Daniel Nordlund Bothell, WA USA
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-- View this message in context: http://www.nabble.com/Need-some-help-tf4624513.html#a13214128 Sent from the R help mailing list archive at Nabble.com.
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
-- Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve?
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
-- View this message in context: http://www.nabble.com/Need-some-help-tf4624513.html#a13216156 Sent from the R help mailing list archive at Nabble.com.
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Jim Holtman Cincinnati, OH +1 513 646 9390 What is the problem you are trying to solve?